<!DOCTYPE html>
<html>

<head>
  <meta charset="utf-8">
  <title>Java后端WebSocket的Tomcat实现</title>
  <script type="text/javascript" src="js/jquery.min.js"></script>
</head>

<body>
<div id="main" style="width: 1200px;height:800px;"></div>
Welcome<br/><input id="text" type="text" />
<button onclick="send()">发送消息</button>
<hr/>
<button onclick="closeWebSocket()">关闭WebSocket连接</button>
<hr/>
<div id="message"></div>
</body>
<script type="text/javascript">
  var websocket = null;
  //判断当前浏览器是否支持WebSocket
  if('WebSocket' in window) {
    //改成你的地址
    websocket = new WebSocket("ws://127.0.0.1:8896/api/websocket/100");
  } else {
    alert('当前浏览器 Not support websocket')
  }

  //连接发生错误的回调方法
  websocket.onerror = function() {
    setMessageInnerHTML("WebSocket连接发生错误");
  };

  //连接成功建立的回调方法
  websocket.onopen = function() {
    setMessageInnerHTML("WebSocket连接成功");
  }
  var U01data, Uidata, Usdata
  //接收到消息的回调方法
  websocket.onmessage = function(event) {
    console.log(event);
    setMessageInnerHTML(event);
    setechart()
  }

  //连接关闭的回调方法
  websocket.onclose = function() {
    setMessageInnerHTML("WebSocket连接关闭");
  }

  //监听窗口关闭事件，当窗口关闭时，主动去关闭websocket连接，防止连接还没断开就关闭窗口，server端会抛异常。
  window.onbeforeunload = function() {
    closeWebSocket();
  }

  //将消息显示在网页上
  function setMessageInnerHTML(innerHTML) {
    document.getElementById('message').innerHTML += innerHTML + '<br/>';
  }

  //关闭WebSocket连接
  function closeWebSocket() {
    websocket.close();
  }

  //发送消息
  function send() {
    var message = document.getElementById('text').value;
    websocket.send('{"msg":"' + message + '"}');
    setMessageInnerHTML(message + "&#13;");
  }
</script>

</html>
